Dr John
I would try both the 200 and 220 Sierra Match Kings and see which bullet your gun prefers.I haven't have much luck with the Berger line of bullets in various rifles but others have so they are worth a try.You can buy the 240's in smaller lots from Brunos shooter supply. www.brunoshooters.com
With a 10 twist they may not stabilise without enough velocity in colder climates.
Lynn

Off of your subject, but I saw that you had a .458 last year I took the trusty ol 458 deer hunting just to have fun and show my friends what it can do for a ranchers deer depridation hunt.

I didn't chrono any of the loads out of my 26 inch barrel. But they probably exceed 2600 fps. 405 grain Barnes X 82 grains of 4320 cci 250.

Classic 110 yard shot near perfect broadside heart lung shot. I had installed a new 2.8 - 10 power 44 mm scope. I shot it about 20 times on a bench rest sighting it in. My shoulder was a little blue and sore. That's half of the man thing shooting a .458 [img]images/icons/smile.gif[/img]

Anyway I cranked it up to 10X and placed the gun on my jacket across the pickup roof standing in the bed. I pulled the trigger and saw the bullet strike. The Mule deer rippled with the impact and threw it sideways about 10 feet.

I have the same RUM (with a Holland QD, trigger job & semi-blue printing).

I was thinking 150 gr Nozler Ballistic tip - if it doesn't like that, 165, then if that didn't work out 180. Why go all the way to 200+?
I'm actually going to try some .308 cal 125gr Noz BT's, but I'm expecting the 1:10 to overstabalize the bullet.
I'll be deer hunting on my buddies ranch in Mt where 3 pts are ez picking, 4 pts give you 10 seconds at 400yds, and 5 pts give you 5 seconds at 5-7 hundred yards. I won't have time for a range finder.
If I want to go to a heaver bullet, I thought I'd use my 338 RUM

are you using a heavy bullet because of wind?, long range consistency? they give the best groups?